I just want don't want to miss anything and get myself in hot water with regulators. 

Water is typically my biggest deal killer.

I’m new to the note investing space and want to start off with buying a partial note to test the waters.

It could be an easy fix like this or a bigger problem depending on the factors at play (are the joists accessible, will it mess anything else up if you just jack it up and reinforce, is there water damage or structural damage to the foundation causing the sag instead of just old joists, anything else going on like a supporting wall or posts under the floor, wiring or plumbing runs involved etc.).

We’ve been tossing around the idea of converting one of our bedrooms into a gym (treadmill, weights, bench, etc with towel and water service).

House hacking is one of the most risk-averse residential investment strategies and will allow you to test the waters and strategically plan from there. 

The classic blue cities, SF, LA, Seattle, NYC, Boston are all the best deep water ports in America. 

@Anthony Vander Meer Does the rent include electricity, heat or hot water?

To address these issues, the lot needs to be properly sloped to divert water away from the building.

If you had to come out of pocket for a water heater for $1,000 in a given month, or a $300 plumbing call, or an AC call, can you comfortably do that type of thing with your finances?